Urgent : Not able to refresh access and refresh tokens automatically in c#.net

Hi,

I have created a c# console application where I am using box windows SDK  in VS 2017 to connect to Box for uploading files to box. I have 2000+  files in database where I am pulling it from database and uploading it to Box one by one. However I could upload 700+ files successfully in 1hr and after 1 hr session gets invalidated even though I am trying to manually update the tokens through code .But the tokens are not getting refreshed and the session gets invalidated.

Below is the code:

string CLIENT_ID = "clientid";

string CLIENT_SECRET = "clientsecret";

string DEV_ACCESS_TOKEN = "accesstoken"; //log into developers.box.com and get this for your registered app; it will last for 60 minutes

string REFRESH_TOKEN = "refreshtoken";

try

{

var config = new BoxConfig(CLIENT_ID, CLIENT_SECRET, new Uri("http://localhost"));

var session = new OAuthSession(DEV_ACCESS_TOKEN, REFRESH_TOKEN, 3600, "bearer");

client = new BoxClient(config, session);  

client.Auth.SessionAuthenticated += Auth_SessionAuthenticated;

client.Auth.SessionInvalidated += Auth_SessionInvalidated;　

AsyncContext.Run(() => MainAsync());

}

public static void Auth_SessionInvalidated(object sender, EventArgs e)

 {

}

public static void Auth_SessionAuthenticated(object sender, SessionAuthenticatedEventArgs e)

 {

DEV_ACCESS_TOKEN = e.Session.AccessToken;

REFRESH_TOKEN =e.Session.RefreshToken;

}